Vistagen (NASDAQ:VTGN), a late clinical-stage biopharmaceutical company pioneering neuroscience with nose-to-brain neurocircuitry to develop and commercialize a new class of intranasal product candidates called pherines, today announced receipt of a "Study May Proceed" letter from the U.S. Food and Drug Administration (FDA) under its U.S. Investigational New Drug (IND) application for refisolone nasal spray, the Company's non-hormonal, non-systemic product candidate in Phase 2 development for treatment of moderate to severe vasomotor symptoms (VMS) (also known as "hot flashes") due to menopause. The FDA's Study May Proceed letter enables the Company to pursue further Phase 2 clinical development of refisolone in the U.S. for a large unmet need in women's health, building on successful exploratory Phase 2a clinical studies for the treatment of menopausal hot flashes and premenstrual dysphoric disorder conducted in Mexico.